Catalytic (Pt-Y) membranes for the purification of H 2-rich streams

Abstract

CO selective oxidation (Selox) for the purification of hydrogen-rich streams was studied in membrane reactors (MRs) using Pt-loaded catalytic membranes. The catalytic membranes were prepared by the ion-exchange of FAU (Na-Y) zeolitic membranes that were synthesized on tubular α-Al 2O 3 supports by a secondary growth method. The catalytic MR tests were performed analysing the CO conversion, O 2 selectivity and yield of the desired reaction. Different feed compositions (CO, O 2, H 2 and N 2 content and O 2/CO ratio), temperatures and pressures were considered with space-time values in the range 0.27–1.2 mg Pt min/cm 3(STP). The CO content in preliminary tests was 10%, 1% in the other experiments. A simulated reformate shifted gas mixture (H 2 = 60%) was also used. A comparison with other literature data for MRs utilizing different membrane types and packed bed traditional reactors with Pt-based catalysts is also provided. The identified ranges of operating conditions (temperature, pressure, feed molar O 2/CO ratio and feed concentration) suggest a profitable use of the catalytic MR (Pt-Y zeolite membranes) for CO Selox after the low-temperature water gas shift unit of a fuel processor converting hydrocarbons into hydrogen-rich gas, operating at similar temperature conditions.